EAPSI: Determining the Biology and Ecology of One of Earth's Earliest animals: Dickinsonia

埃迪卡拉生物群的化石，代表了地球上最早的宏观多细胞生物的证据。这种多样的软体生物动物群有助于弥合地球早期大部分历史中已知存在的微小单细胞生命形式与今天存在的复杂、熟悉的形式之间的进化差距。狄更逊水母是这一生物群中常见而多样的成员，然而人们对它的了解仍然很少。确定这种早期生物的生态学和生物学将为我们理解早期生命的进化提供关键的见解。在南澳大利亚的弗林德斯山脉地区发现了大量的化石，其中包括数百个狄金森水母，其中许多化石都存放在南澳大利亚博物馆（SAM）。前往南澳大利亚可以访问这一无与伦比的数据集，并允许与该地区标本的主要专家Jim Gehling博士（SAM）合作。对来自南澳大利亚埃迪卡拉纪沉积物的狄金森水母的研究将进行，以检验两个假设：1)先前确定的物种差异可以通过形态差异来识别，而不是不同保存模式的产物；(2)狄更逊水母是埃迪卡拉动物群中数量最多的生物之一。数据还将用于解决大小、频率和空间模式能在多大程度上告诉我们这种独特生物的特性和协同作用。这些假设将通过四个目标进行检验：1)识别形态变异，以调查物种形成；2)利用整个床面照片以及狄金森水母存在、不存在和丰富程度的详细报告来确定优势地位和环境偏好；3)在床尺度上对其大小和丰度的观测以及与其他分类类群的空间关系也将被记录下来，以检验这一古老生物的生态重要性；4)评估该化石记录中潜在的保存偏差。NSF EAPSI奖是与澳大利亚科学院合作资助的。

Fossils of the Ediacara biota, represent the earliest evidence of macroscopic, multicellular organisms on Earth. This diverse fauna of soft-bodied organisms helps to bridge the evolutionary gap between microscopic, unicellular life forms known to exist through most of Earth's early history and the complex, familiar forms that exists today. Dickinsonia is a common and diverse member of this biota, however it remains poorly understood. Determining the ecology and biology of this early organism will provide critical insight to our understanding of the evolution of early life. Abundant fossils, including hundreds of Dickinsonia have been identified in the Flinders Ranges area of South Australia and many are housed in the South Australia Museum (SAM). Travel to South Australia will allow access to this unparalleled data set and permit collaboration with Dr. Jim Gehling (at the SAM), the premier expert on specimens from this region.Study of Dickinsonia from the Ediacaran deposits of South Australia will be conducted in order to test two hypotheses: 1) previously determined species distinctions can be identified using morphologic differences and are not an artifact of varying preservational modes; and 2) Dickinsonia had preferred environmental habitats and was one of the most abundant organism of the Ediacara biota. Data will also be used to address the extent to which size frequency and spatial patterns can inform us about the autecology and synecology of this unique organism. These hypotheses will be tested through four objectives: 1) identify morphological variability in order to investigate speciation; 2) to determine dominance and environmental preference using photographs of entire bed surfaces along with detailed reports of presence, absence, and abundance of Dickinsonia; 3) bed scale observations of size and abundance data will also be documented as well as spatial relations between Dickinsonia and other taxonomic groups to examine the ecologic importance of this ancient organism; and 4) evaluate potential preservation biases in this fossil record. This NSF EAPSI award is funded in collaboration with the Australian Academy of Science.